Spinner's weasel or clock reel is a mechanical yarn-measuring device consisting of a spoked wheel with gears attached to a pointer on a marked face and an internal mechanism that makes a "pop" sound after the desired length of yarn is measured. The pointer allows the spinner to see how close they are to reaching a skein. The weasel's gear ratio is typically 40 to 1, and the circumference of the reel is usually two yards, thus producing an 80-yard skein when the weasel pops.